Electronic timepieces are known having optical displays, readout controls and setting controls, as illustrated for example by U.S. Pat. Nos. 3,672,155 to Bergey et al and 3,810,356 to Fujita, and such timepieces may include an alarm capability, illustrated for example by U.S. Pat. Nos. 3,636,549 to Berman et al, 3,664,116 to Emerson et al, 3,727,395 to Baylor, 3,745,761 to Tsuruishi, and 3,759,029 to Komaki.
The electronic watch of the present invention may provide both optical and audible readout capabilities. In the audible readout mode, the present instrument uses an electroacoustic transducer to produce tone signals, and the transducer desirably takes the form of a small earphone such as is used in a conventional hearing aid or dictating machine. Such a transducer may serve also as the control device or member in the present invention, since it is found that a sharp tap on such a transducer produces a voltage pulse having an amplitude of the order of 1 volt. This is of course many times greater in amplitude than that caused by the loudest sound, and the voltage pulse so produced then serves as a signal for interrogation or control of the present apparatus. Alternatively, the interrogation or control signal may be produced by a pushbutton switch suitably connected to the battery power supply. If no audible readout capability is desired, certain of the circuitry hereinafter shown and described may be eliminated. Even if the audible readout of time is foregone, it may nevertheless be desirable to retain the transducer, in order to provide the alarm capability as well as auxiliary functions performed by such transducer, including an automatic hour strike and an acknowledgment beep occuring immediately after the first interrogating tap by the user, confirming that the tap was sharp enough to generate a voltage of sufficient amplitude to commence operation of the circuitry.
An important feature of the present invention is its use of only a single control member, actuatable by the user, to accomplish the various functions, including an audible readout of clock time, optical readouts of clock time, alarm time and information in an auxiliary register, and the changing of the settings of time and other stored information. Interrogation and control of the timepiece are accomplished by one or more pulses in a pulse train, each pulse being produced by the user's actuation of the control member. The number of pulses in the train, and their chronological spacing within the train, are significant in causing the desired control of the timepiece. In its stopwatch mode, the user may use the timepiece to time events repetitively as desired, and the same electronic counters which are used in the stopwatch mode also serve to store an alarm time selected by the user. Furthermore, the same counters are also used for precision setting of the seconds and minutes of the clock time of the instrument.
The invention also provides security means for minimizing and virtually eliminating the possibility that a random series of control signals might change or otherwise affect any of the settings of the instrument. In the present form of the invention, the security means comprises circuitry which is effectively responsive to a user-produced pulse only during a narrow time gate constituting a short interval -- illustratively 0.5 second -- immediately following an optical display of longer duration; actuation of the control during the optical display period aborts operation and restores the timepiece to quiescent state.
As used herein, a pulse train is understood to mean a single user-produced pulse or a series of such pulses whose number and chronological spacing are significant in causing the circuitry to respond as desired by the user, either in interrogating a readout or in changing the setting of one or more of the instrument counters.
The optical display desirably includes a seven-segment array for each decimal digit, and the segments may be of the light-emitting diode (LED) type or liquid crystal displays (LCD).
Accordingly, a principal object of the present invention is to provide a novel electronic timepiece. Additional objects are to provide such a timepiece having multiple readout capabilities interrogatable by the user through one of a plurality of predetermined pulse trains consisting of one or more pulses produced by actuation of a single control member; to provide in such a timepiece a stopwatch or duration register providing not only stopwatch capabilities but also used as an alarm register; to provide in such a timepiece means for using the duration register to provide an optical display of changes made during precision setting of the seconds and minutes of clock time, to provide in such a timepiece security means to virtually eliminate the possibility that control signals at random times might adversely affect the various settings of the instrument; and for other and additional purposes as will be understood from the following description of the invention, taken in connection with the accompanying drawings.